Got a Mk 10 joystick which has a 2900mAh battery in it, run time is 1.5 hours on full

I want to run an additional battery to supply it, but am after a cheaper alternative than the Exposure support cell (£40)

So if it drains a 2900 battery in 1.5 hours, do i need a powerbank type battery that can supply at least 2A?

Tried with an Anker Lipstick but this will only charge it, not supply power when the light is on, but just checked and the Anker is only rated at 1A so i’m assuming it cuts the power to the light as the current draw is too much.

Amazon has some 2-2.4A USB power banks so am looking at those. eg

https://www.amazon.co.uk/Portable-RAVPower-External-Technology-Smartphones/dp/B00X9VKZIO/ref=sr_1_7?ie=UTF8&qid=1474533706&sr=8-7&keywords=2A+lipstick+power+bank

EDIT actually the specs on that are confusing as lower down it says only 1A.

This one may work
https://www.amazon.co.uk/RAVPower-Portable-Charger-External-Technology/dp/B00Y2RFNI6/ref=sr_1_4?ie=UTF8&qid=1474533005&sr=8-4&keywords=2a+power+bank.

Its amazon though so i can easily return it if doesnt work!

Can it charge and operate at the same time?

yeah its supposed to do that with the official support cell, just draws from both batteries at once i think.

I’d spend the £40 and know you’re getting something that’ll be

a) waterproof
b) rugged
c) designed to work with the lamp

(although clearly this doens nothing to answer your question but imo all of those lipstick things are designed to power phones which have a (relatively) low current draw and I’d be reluctant to use them in a high drain application).

Its not quite as simple as matching up the current.
99.9% of cheap power banks like you linked are designed to charge 5V devices that are usually charged via USB.
Exposure don’t publish the details of their batteries, but there’s a good chance they are 7.4V. No idea what would happen if you plugged in a 5V power bank to the smart port, its entirely possible your light would try to deliver current to the power bank rather than the other way around.

ah yes hadnt thought about the voltage.

Looks like the exposure support cell is what i need then. Or just ride at lower power!

What you need is a MaxxD on the bars – 13 hour run time on low 😉

Support Cells are 3.7v. It is just a single 18650 cell with a battery protection circuit, nothing more. I’ve made a few 2cell versions (2 cells in parallel) to power my Joystick in long races. Works fine. All the intelligence is in the light itself – if you plug in a 3.7v source like a support cell it will essentially draw power from both the internal and external batteries simultaneously. If the internal cell is more discharged than the external one, it will balance them to the same state of charge.
If you plug in a >4.2v source (charger or USB), it will use it to charge the internal battery. Not sure if it will allow you to use the light at the same time, can’t remember trying this. It will certainly allow you to have the light on, can’t remember if it will actually charge though.
Hope this helps!

Just make a 4 cell, 18650, 2 series, 2 parallel, that’ll do you, and buy a smart charger to charge the cells individually. Think I have a battery holder rigged just for that floating round somewhere, all it needs is a wire and the correct plug. Can you solder and use a voltmeter?

4 cell 2s2p pack would be too high a voltage. it would need to be 4p so the voltage is still 4.2-3.7V with somewhere between 9 and 12 mAh depending on the cells

smudge from mtbbatteries will make you up a set if you’re after one

EDIT – strange double post!

I’ve a triple cell extreme rap battery made by Mtb batteries. It will power a Diablo for 4hours on full beam (including the one hour the internal battery gives)

Is waterproof and works well. Custom length cable too…